Septum (coral)

In corals, a septum (plural septa) is one of the radiating vertical plates lying within the corallite wall. Outside the corallite wall these plates are known as costae (singular costa). The septa may be thick, thin or vary in size. They may have teeth which range from needle-like to blade-like and are often characteristic of different genera.

References

Septum

In biology, a septum (Latin for something that encloses; plural septa) is a wall, dividing a cavity or structure into smaller ones.

Examples

Human anatomy

Histological septa are seen throughout most tissues of the body, particularly where they are needed to stiffen soft cellular tissue, and they also provide planes of ingress for small blood vessels. Because the dense collagen fibres of a septum usually extend out into the softer adjacent tissues, microscopic fibrous septa are less clearly defined than the macroscopic types of septa listed above. In rare instances, a septum is a cross-wall. Thus it divides a structure into smaller parts.

Septum (cell biology)

A septum in cell biology is the new cell wall that forms between two daughter cells during the telophase phase of cell division.

In yeast, septins form a ring structure, to which other proteins are recruited. In particular, chitinase 2 is required, an enzyme that synthesises chitin thereby building up the primary septum. A secondary septum of β-glucans and mannoproteins is then assembled, and the primary septum degraded during cell separation.

References

Septum (cephalopod)

Septa (singular septum) are thin walls or partitions between the internal chambers (camerae) of the shell of a cephalopod, namely nautiloids or ammonoids.

As the creature grows, its body moves forward in the shell to a new living chamber, secreting septa behind it. This adds new chambers to the shell, which can be clearly seen in cross-sections of the shell of the living nautilus, or in ammonoid and nautiloid fossils. The septa are attached to the inside wall of the shell, thus dividing the phragmocone into camerae.

Where the septum meets the shell a suture line forms; in some ammonoids these lines became extremely complex and elaborate, providing strength without the necessity of added weight. Elaborate sutures allowed for thinner shells, and hence less time needed for shell growth and less time spent in the vulnerable juvenile stage.

The nature and structure of the septa, as with the camerae, and siphuncle, and the presence or absence of deposits, are important in classification of nautiloids. In some nautiloids, such as the Orthoceratidae, the septa tend to be widely spaced, resulting in large, long camarae. In others such as the Ellesmerocerida, Oncocerida and Discosorida the septa are crowded closely together. In some straight-shelled forms like Actinoceras, calcium carbonate deposits extend from the camera (mural deposits) to the septa (episeptal deposits).

Coral

Corals are marine invertebrates in the class Anthozoa of phylum Cnidaria. They typically live in compact colonies of many identical individual polyps. The group includes the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.

A coral "group" is a colony of myriad genetically identical polyps. Each polyp is a sac-like animal typically only a few millimeters in diameter and a few centimeters in length. A set of tentacles surround a central mouth opening. An exoskeleton is excreted near the base. Over many generations, the colony thus creates a large skeleton that is characteristic of the species. Individual heads grow by asexual reproduction of polyps. Corals also breed sexually by spawning: polyps of the same species release gametes simultaneously over a period of one to several nights around a full moon.

Although some corals can catch small fish and plankton, using stinging cells on their tentacles, most corals obtain the majority of their energy and nutrients from photosynthetic unicellular dinoflagellates in the genus Symbiodinium that live within their tissues. These are commonly known as zooxanthellae and the corals that contain them are zooxanthellate corals. Such corals require sunlight and grow in clear, shallow water, typically at depths shallower than 60 metres (200 ft). Corals are major contributors to the physical structure of the coral reefs that develop in tropical and subtropical waters, such as the enormous Great Barrier Reef off the coast of Queensland, Australia.

Precious coral

Precious coral or red coral is the common name given to Corallium rubrum and several related species of marine coral. The distinguishing characteristic of precious corals is their durable and intensely colored red or pink skeleton, which is used for making jewelry.

Habitat

Red corals grow on rocky seabottom with low sedimentation, typically in dark environments—either in the depths or in dark caverns or crevices. The original species, C. rubrum (formerly Gorgonia nobilis), is found mainly in the Mediterranean Sea. It grows at depths from 10 to 300 meters below sea level, although the shallower of these habitats have been largely depleted by harvesting. In the underwater caves of Alghero, Sardinia (the "Coral Riviera") it grows at depth from 4 to 35 meters. The same species is also found at Atlantic sites near the Strait of Gibraltar, at the Cape Verde Islands and off the coast of Southern Portugal. Other Corallium species are native to the western Pacific, notably around Japan (Corallium japonicum) and Taiwan; these occur at depths of 350 to 1500 meters below sea level in areas with strong currents.

Gala Coral Group

Gala Coral Group Ltd is a British betting shop, bingo and casino operator owned by private equity firms Candover Investments, Cinven and Permira. In October 2005 it merged with Coral Eurobet for £2.18 billion. The acquisition made it the UK's third largest bookmaker and largest bingo operator. It owns over 30 casinos. Coral will remain a brand and trading division of the new group.

The Group headquarters are in Nottingham (Gala Bingo and Casino), Stratford, London (Coral), and Woking (Gala Coral Remote Gaming). However, in 2011, a decision was made to move substantial parts of the business to Gibraltar, including almost all of the remote gaming division.

The group, through acquisitions and new developments have over 1800 licensed betting offices.

In July 2015, it was announced that Ladbrokes would merge with its slightly smaller rival Gala Coral, and that Ladbrokes' CEO, Jim Mullen would become the CEO of the new company, Ladbrokes Coral.

Group divisions

Gala Bingo

Gala Bingo operates 137 clubs throughout the UK, with approximately a 24% share of all clubs and nearly 40% of National Bingo Game ticket sales up until the operator's withdrawal from the National Game in Summer 2008.